The present invention provides devices, methods, and kits for convenient determination of male fertility parameters. More specifically, the present invention is able to detect semen samples having a sufficient concentration of motile sperm to support fertility. The devices, methods and kits of the present invention provide easy, one-step assays for such determinations.
Fertility testing is becoming more widespread as increasing numbers of apparently infertile couples seek medical assistance in conception. Because reproductive abnormalities of both sexes may affect fertility, assessing male fertility is common in fertility evaluations.
Male infertility may be due to a number of factors, including hormonal anomalies, work place exposures, and sequelae of infectious diseases. Even common childhood illnesses such as mumps may cause male infertility. Thus, most males are at some risk for infertility and should be evaluated in any fertility work-up.
The most common starting point for evaluation of male fertility is an assessment of the sperm count in semen. The most commonly accepted figure as the lower limit of normal is 20.times.10.sup.6 motile sperm per milliliter. Even more important to fertility than absolute sperm count, however, is sperm motility. Fertility Study, 31:305 (1979). Therefore, in male fertility analyses sperm motility must also be determined.
Currently available techniques for measuring sperm count and sperm mobility are microscopic in nature. Sperm morphology and motility is visually assessed by laboratory technicians. Because semen evaluation is essentially qualitative, substantial experience is required for accurate evaluation by the technicians. The high level of experience required by laboratory technicians precludes general office evaluation of semen samples and generally requires referral to a reference laboratory. Further, debris in semen samples can cause erroneous or inconsistent results.
Accurate assessment of sperm motility also requires that the semen sample be fresh. Since the sample must be analyzed by a reference laboratory, the sample must usually be obtained at the laboratory. Often this requires additional appointments at medical facilities and time away from work. This can be inconvenient for many patients and even a hardship for patients living in rural areas far away from reference laboratories.
Attempts to develop biochemical assays of semen have not resulted in simple procedures which may be performed in the physician's office. Most biochemical markers have failed to demonstrate correlations with either sperm number or motility. Fumarase activity, an enzyme present in semen, has been found to correlate to both sperm count and percentage motility. Crabbe, J. Reprod. Fert., 51:73-76 (1977). Crabbe measured fumarase activity by spectrophotometric measurements. Unfortunately, spectrophotometric assays are not generally suitable for office assays because of the cost of these specialized devices as well as the training required for accurate and reproducible operation.
What is needed in the art is a simple assay for assessing sperm count and motility that does not require expensive specialized instrumentation or extensive training. One step assays that could be performed according to easy to follow instructions without specialized training would be optimal. Surprisingly, the present invention satisfies these and other needs.